In order to study altruism, suppose that a researcher interviews 500 individuals about their charitable behaviors. To check the accuracy of certain responses, he persuades officials of local charities to provide the names of those who have donated during the past year. Results indicate that over 40 percent of those who say they have donated to these charities have not actually done so. The researcher writes an article discussing the implications of this fact for solicitation of donations, and the article is published in a professional journal. He also releases the results of his study to the local newspapers and provides names of the "liars" to the directors of the local charities so that they can contact these people and ask for the donations they claim to have made.
A researcher wishes to conduct a study of the effects of a person's upbringing on the likelihood of that person's becoming a child abuser. She plans to interview people and talk about their parents' child-rearing practices. She will also try to interview a third person (an old family friend or relative, for example) who can independently report on how a person's parents raised him or her and on whether that person is abusive to his or her children. Finally, the researcher will collect information from official records and interview family physicians in an attempt to obtain valid, reliable data on the actual incidence of child abuse.